1. Field of the Invention
The present invention relates to a telescopically extendable and retractable arm including a supporting member and a plurality of telescoping members of decreasing diameter located in the supporting members.
2. Description of the Prior Art
Telescopically extendable and retractable arms of the kind referred to find a plurality of technical applications such as e.g. extendable stands or telescoping pillars or also as supporting members or arms, respectively, for industrial robots and similar apparatuses.
These structures give, however, rise to difficulties in that a plurality of features are demanded which actually hinder each other, namely a large supporting power in both directions in the longitudinal direction of the arm, a smooth and reproducible extending and retracting, an absorbing of eccentrically acting loads, a large length of stroke but simultaneously a small structural height in the retracted position, low proper weight, high stiffness or rigidity, respectively, as well as in some specific applications such as tripods for cameras, a noiseless operation.
Generally available conventional telescoping arms meet above demands in part only.